A pressure-sensitive adhesive product such as a pressure-sensitive adhesive film may have various uses such as a protective film, an advertisement film, a cleaning sheet, a reflective sheet, a structural pressure-sensitive adhesive sheet, a pressure-sensitive adhesive sheet for a photograph, a pressure-sensitive adhesive sheet for displaying a traffic line, an optical pressure-sensitive adhesive product, a pressure-sensitive adhesive product for an electronic part or a medical patch.
Such a pressure-sensitive adhesive film may include various kinds of plastic films as a substrate. The plastic film is conventionally manufactured by melting a thermoplastic resin and applying the melted resin to a T-shaped die, extrusion or calendaring method.
However, a projecting part so called as a fish eye is frequently formed on the substrate film prepared by a conventional method, the film has a non-uniform thickness, and there is significant variation in physical properties according to an axis direction, which limits application of the substrate film.